Mine is always something I was eating while there:
Vegas---crepes and Gouda cheese from Paris buffet, pizza from Hidden Pizza
Disney---Pecos Bill's nachos (something about their taco meat!) and anything from Les Halles
Louisiana---hurricanes, Cajun Mary's, Cajun chicken poboys, beignets
Mississippi---BBQ, fried chicken, any kind of cooked greens (turnip, collard, etc)
New Mexico---everything smothered in green chiles, blakes lotanurger